Exploring the Antimicrobial Potential of Carica papaya and Tithonia diversifolia Extracts against Fusarium verticillioides in Maize

Abstract

Fusarium verticilloides is one of the most common contaminants that reduces the quality and quantity of yield in maize. This study investigates the effectiveness of plant extracts in the management of the leaf spot disease caused by this pathogen in Maize. The biocontrol potentials of aqueous extracts obtained from Tithonia diversifolia and Carica papaya leaves at 25, 50, and 75% concentrations were investigated against pathogenic F. verticillioides. Punctured pots were laid out in a completely randomized design (CRD) in the screenhouse. The treatments are as follows: T1= control (uninoculated maize), T2 = Maize + FV + Cp, T3 = Maize + FV +Td, T4 = Maize +FV +Cp +Td, T5 = Maize + Fv, T6 = Maize +Cp, T7 = Maize+ Td, T8 = Maize+ Cp + Td. The treatments were monitored on maize varieties and repeated thrice. The two extracts were effective against the pathogen in vitro, with Tithonia diversifolia (2.42 cm) producing a more significant effect in suppressing the mycelia growth compared to Carica papaya (2.70cm) and the two combined (2.64 cm). The efficacy of the extracts increased with concentration. Although no significant (p<0.05) difference was recorded between 25% and 50% concentrations, while 75% extract concentration was the most effective. The screen house evaluation showed that C. papaya, T. diversifolia and their interactions inhibited the pathogen considerably. In the in vitro study, there was a positive and significant association between the study period and the mycelia growth; however, in the in vivo study, the relationships between the growth characters were positive and highly significant. Hence, the biocontrol potential of the extracts of C. papaya and T. diversifolia can be harnessed in the management of leaf spot disease of maize and could also serve as a suitable alternative to the use of synthetic fungicides.